The Super Admin role allows a user to perform all possible capabilities. Each of the other roles has a decreasing number of allowed capabilities. For instance, the Subscriber role has just the “read” capability. One particular role should not be considered to be senior to another role. Rather, consider that roles define the user’s responsibilities within the site.

A Role defines a set of tasks a user assigned the role is allowed to perform. For instance, the Super Admin role encompasses every possible task that can be performed within a Network of virtual WordPress sites. The Administrator role limits the allowed tasks only to those which affect a single site. On the other hand, the Author role allows the execution of just a small subset of tasks.

is used to determine whether a user can access the Network Upgrade page in the network admin. Related to this, the capability is also checked to determine whether to show the notice that a network upgrade is required. The capability is not mapped, so it is only granted to network administrators. See #39205 for background discussion.

is used to determine whether a user can setup multisite, i.e. access the Network Setup page. Before setting up a multisite, the capability is mapped to the `manage_options` capability, so that it is granted to administrators. Once multisite is setup, it is mapped to `manage_network_options`, so that it is granted to network administrators. See #39206 for background discussion.